User manual

DCM500,
500
Watt
Power
Amplifier
Product Description
The DCM500
is
a 500 watt
power
amplifier
in a two rack
unit
(2RLI)
chassis
suitable for table
or direct
19" rack
mounting.
The
DCM500
has
outputs
for
70 & 100
volts and 4
ohms.
It
has
a balanced input
of 10K
ohms. The DCM500
will
operate from 240
V AC
@
50
IIz
or I I
0 VAC
@
60 Hz
(not
user selectable, internal,
factory
adjushent only,
specifi at the
time
of ordering)
or 24
VDC
and will meet
it's
full
performance
specification
on either
voltage supply.
The DCM500
also features
a
DC
battery trickle
charge facility,
slow start
on
powering
up
(to
reduce inrush
current
problems),
auto-sensing
ftn cooling,
plus
overload
short circuit
and over
ternperature
protection.
The maximum
recommended load
for the DCM500
is 20
ohms.
lnitial
Set Up
There
is an unlabelled,
screwdriver
adjustable
output level
control located
centrally
on
the front
panel
of the DCM500.
Turning
this
control in
the clockwise
direction
will
increase
the
power
output,
turning
this comtrol in
a counter-clockwise
direction will
reduce
the
power
output.
The
ftctory
default setting for
this conkol is
such
that a I volt input will
give
a 100 volt
output.
Front
Panel
Gontrols
Output
Level:
The
output level
control is
unlabelled,
r@essed
(screwdriver
adjustable)
and is located in
the centre
of
the
front
panel,
just
to
the right
of the DCM
Series logo. Tuming
the
control clockwise
will increase
the
output of the DCM500
towards
it's manimum
output level
wtrile
tuming
the
control counter-clockwise
will
decrease the
output level. Adjust
this control
for
the desired
output level
depending
on the level
of the
input
signal
(from
a mixer
or other
signal
source).
The
factory
defrult
setting for
this control
is such
that a I
volt input
will
give
a 100 volt
output.
POWef
SWitch:
The rocker
switch located
in
the front
centre of the
panel
turns AC
power
on to the DCM500.
Rocking
the
power
switch
to the right
to
turns the AC
powetr
'on'.
When
the
AC
power
is
'on',
a
gree,lr
LED
will
glow
in
the amplifier
status
display
windorv. Please
note that
this switch
does
not switch DC voltage.
If
a
DC
voltage supply
is connected
to the DCM500,
the
amplifier will
operate
as sfi)n
as the connection
is
made, regardless
of the
position
of the AC
power
switch. If
both an AC
and
DC voltage
supply
are
connected and
you
rock
the AC
power
switch
to the
'off
position,
the DCM500
will automatically
continue to
op€rate normally
from the
DC
supply
(and
the
'mains
failure'
LED in the
amplifier
status display window
will also
glow
undo
these comditions;
see the
amplifio
status
display window
section under Frurt Panel
Cmtols
later in
this manual).
Gooling
Fans
(Air
lntake):
rhe
cooling fans
(two
installed
in the
case of the DCM500)
are ternperature
sensitive
and
only switch
orr when the
temperature
of the
DCM500
had reached
a
pre-determined
range. The
fans will
stay on and
only switch
off again
mce the temperature
of the DCM500
has
fallen
below a
pre-determined
level.
So,
the ftct that the fans
are
not
operating
at any time
(and
most noticeably
to
the operator
at turn-on)
does
not
mean
that the
amplifier is faulty in
any way,
just
that it is
o'perating within
a
temperature
range
that does not need
frn
cooling for
adequate heat
dissipation. If
the DCM500
is
operating
curtinually
at
c.onservative levels
and
proper
load
conditions,
it is
possible
that
the cooling fans
will
not
switch
on
at
anytime
during normal
operation. When
operating,
the fans
cause air flow from
the front
to the rear
of the DCM500.
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